Technical Abstract: In 2006, EPA implemented a more stringent standard for PM2.5, particulate matter whose effective diameter is less than 2.5 microns. PM2.5 is listed as a criteria pollutant in the National Ambient Air Quality Standards (NAAQS). All cotton gins across the cotton belt will be impacted by this standard. For example, a district in California has proposed to include cotton gins in their PM2.5 State Implementation Plan (SIP) under the assumption that the PM2.5 emissions from cotton gins are significant enough to warrant further study. Further, the district is considering additional control measures above and beyond the current mandate to install enhanced “1D-3D” cyclones on all emission points such as baghouses, series cyclones, and other technologies which can have substantially higher fixed and variable costs compared to current control measures. If additional control measures such as baghouses are mandated, the costs will be significant and will likely impact ginning costs.
The primary issues associated with implementing this standard are: 1) very limited cotton gin PM2.5 data are available; 2) sampler errors, recent research indicates that current PM2.5 sampling methods could be over-estimating cotton gin PM2.5 emission concentrations by 14 times; and 3) over-prediction of dispersion models, some studies in the literature suggest that these models could be over-predicting cotton gin boundary line concentrations by more than four times the actual concentrations. In response to these issues, the cotton ginners’ associations across the cotton belt, including the National, Texas, Southern, Southeastern, and California associations, agreed that there is an urgent need to collect gin emissions data that may be used to refute inaccurate data used by state regulatory agencies. Working with the cotton ginning associations across the country and state and federal regulatory agencies, Oklahoma State University and USDA-ARS researchers developed a proposal and sampling plan which was initiated in 2008. This five-year project involves extensive stack and ambient sampling at seven cotton gins across the county. This paper will serve as a progress report of the accomplishments achieved four years into the projects and plans for the coming year.